Rs-232 Control - Extron electronics MLA-VC10 User Manual

Installation and Setup, cont'd
Operation
To control audio volume when using an MLA-VC10, turn a
connected MediaLink Controller's Volume knob, or send
commands via an RS-232 remote control device such as a
computer or third party control system.
If you are using an MLC with the
MLA-VC10, use the
Controller (MLC) Config portion of
the MediaLink control software
(included with the MLC) to set the
MLC's volume control to
"Switcher" instead of "Projector" .
Refer to the MediaLink Controllers
User's Manual for details.

RS-232 control

The RS-232 protocol for the MLA-VC10 is 9600 baud, 1 stop bit,
no parity, and no flow control.
The control device (host) can use Extron's Simple Instruction Set
(SIS) commands.
The MLA's MLC/Power 5-pole captive screw connector has the
following pin assignments:
A = transmit, B = receive, C = not used,
= ground, + = +12VDC input
Host-to-MLA communications
SIS commands consist of one or more characters per field. No
special characters are required to begin or end a command
sequence. When a command is valid, the interface executes the
command and sends a response to the host device. All respon-
ses from the interface to the host end with a carriage return and
a line feed (CR/LF =
character string. A string is one or more characters.
MLA-initiated messages
When the MLA is powered up, it sends the following message
(underlined here) to the host:
(C) Copyright 2002, Extron Electronics, MLA-VC10
No response is required from the host. The MLA may also send
a message of Volxxx where xxx represents the setting for the
percentage of maximum volume.
MLA-VC10 • Installation and Setup
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), which signals the end of the response
Error response
When the MLA receives a valid SIS command, it executes the
command and sends a response to the host device. If the MLA
is unable to execute the command because the command
contains invalid parameters, it returns the following error
response to the host:
E13 – Invalid value (the number is out of range/too large)
Using the command/response table
The command/response table lists valid command ASCII codes,
the MLA's responses to the host, and a description of the
command's function or the results of executing the command.
Lower case characters are acceptable in the command field
unless otherwise indicated. The following ASCII to HEX
conversion table is for use with the command/response table.
ASCII to HEX Conversion Table
Symbol definitions
= CR/LF (carriage return/line feed) (hex 0D 0A)
• = Space
X1 = Volume adjustment range (0 through 100%)
= On/off status
X2
0 = off/disable
1 = on/enable
= Controller firmware version (listed to
X3
two decimal places e.g.: x.xx)
MLA-VC10 • Installation and Setup
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